 Let me now address the situations where there is no conflict rule in any of the conflicting treaties. Which treaties should prevail? Absent any rule governing the conflict between obligations, the crucial distinction to be made is whether the two successive and conflicting treaties are binding on exactly all the same parties or not. Let me explain this, it's fairly technical. In case of successive treaties that are binding on all the same parties, article 30 paragraph 3 of the Vienna Convention gives preference to the later treaty by saying that I quote, the earlier treaty applies only to the extent that its provisions are compatible with those of the later treaty. And of course, in other words, and to use again a Latin phrase, lex posterior derogat priori. The later treaty prevails between the parties and the earlier treaty, which has not been terminated, only applies to the extent it is compatible with the obligations under the new treaty. Giving preference to the obligations arising from the more recent treaty is a sensible solution because one can presume that states have concluded the new treaty knowing what their prior obligations are. And that if they decided to have new obligations conflicting with the old ones, it was precisely in order to replace the old ones by the new ones. As all the parties to the earlier and the later treaties are the same, there is no risk that any of them concluded the new treaty in order to escape prior commitments. But what happens if the parties to the later treaty do not include all the parties to the earlier one? What happens if the earlier treaty was concluded between A, B, C and D, but that only A, B and C have concluded the later treaty leaving D out of it? In such a case, if preference is given to the later treaty, then D would be deprived of its rights under the earlier treaty. Applying lexposteriori in such a case would amount to lawfully permit to circumvent commitments made under the old treaty, and indirectly encourage states to conclude a new treaty in order to deprive some parties to the old treaty of their rights under that treaty. However, as a matter of treaty law, such deprivation cannot occur without the consent of the parties to the earlier treaty, which are not bound by the new treaty. Then what should be done when the parties to the later treaty do not include all the parties to the earlier one? Article 30, paragraph 4 of the Vienna Convention does not provide for a uniform solution and requires to make distinctions according to the specific relations that are at stake. In the relations between the parties that are bound by both treaties, the same solution applies as when the parties to the earlier treaty and the later treaty are identical. So in the example I gave earlier, between A, B and C, the later treaty applies and the earlier treaty will only apply between them to the extent that its provisions are compatible with those of the later treaty. However, in the relations between a state party to both treaties and a state party to only one of the treaties, the treaty to which both states are parties governs their mutual rights and obligations under article 30, paragraph 4, B. This means in my earlier example that between D and any other states A, B or C, the early treaty is the only treaty common to all of them and therefore the only to apply between them. In other words, D can require from A, B or C that they continue to perform the earlier treaty in its favor even at the cost of a breach of the later treaty between them. And if A, B or C choose not to perform the earlier treaty in favor of D, then any of them would be responsible vis-à-vis that state. In other words, an issue of responsibility for the breach of either of the conflicting treaties will be unavoidable. And if the breach is a material breach within the meaning of article 60 that we studied before, then the issue of the suspension of or determination of the breach treaty may occur. Article 30, paragraph 5 of the Vienna Convention recognizes that. In other words, there is no perfect harmonious solution to all cases of conflicting treaties. And a state will sometimes have to make a choice between its various treaty obligations. The choice between preferring one obligation over another one will be unavoidable because performing one treaty will necessarily entail the breach of the other treaty. And that choice is not controlled by pre-existing legal rules on the basis of the nature of the treaty at stake. Is it, for instance, a human rights treaty or a trade agreement? Or on the basis of the special or general character of the respective treaties? Is it a humanitarian law treaty or a human rights treaty? Or on the basis of the nature of the parties at stake? Is it a treaty owed to another state or to another international organizations? At the end of the day, the choice to be made by the state will be a political choice rather than a legal choice because it will not be directed by legal rules. But of course the state will also make its choice in light of the respective consequences and costs resulting from each of the potential breaches. And those costs are issues of responsibility under international law.